halt_rollout

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden. It transparently discloses the key behavioral trait: halting stops delivery to new users while preserving the current userFraction, and implies reversibility by recommending update_rollout to resume. It doesn't detail edge cases or side effects, but covers the core behavior well.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the verb, zero fluff. The first sentence states the action and effect, the second provides the recovery path. Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has 4 parameters (1 required) and no output schema. The description covers the purpose, the effect on userFraction, and the follow-up action. It doesn't explain return behavior, but that's not critical for a straightforward mutation. It is complete enough for an agent to select and invoke correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all four parameters (track, package_name, validate_only, changes_not_sent_for_review) are already documented in the schema. The description adds no additional parameter-specific context beyond the schema, but doesn't need to thanks to high coverage. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Halt') with a specific resource ('in-progress staged rollout on a track') and clearly explains the effect ('stopping delivery to new users while keeping the current userFraction'). It also distinguishes from sibling update_rollout by recommending it for resume/complete, exceeding a basic purpose statement.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description states when this is appropriate: for an 'in-progress staged rollout', and it explicitly directs to 'use update_rollout afterwards to resume or complete it' as the follow-up alternative. It doesn't explicitly contrast with promote_release or mention when not to use, but the context and follow-up provide clear guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.